Wind turbines (e.g., GE Energy 1.5 mw series wind turbine found at http://www.gepower.com), water turbines, and wave turbines (e.g., Islay Wave Power Station in Scotland, UK) have been developed for, among other things, generating electrical power. However, because the wind speed is variable, because tidal and wave characteristics such as height and flow rate vary with many factors including time of day, seasons, weather variations and lunar cycles, the electrical power produced by generators powered by such (hereinafter called “environmentally powered generators”) is typically produced at electrical frequencies which vary widely and somewhat randomly with related natural phenomenon. Because power generation (into the power distribution grid) and power obtained by users receiving power from such a generator or the grid needs to be at or very close to a selected and stable frequency, like 60 Hertz (Hz) in the United States, the power from the environmentally powered generators must be converted to the desired or selected stable frequency by suitable frequency conversion devices (e.g., the 1.5 mw series GE wind turbines are reported to be connected to a pulse width modulated IGBT frequency converter). Devices for converting input power at variable frequency to output power at a stable frequency are believed to be inefficient. As a result, it is believed that much useful power or electrical energy generated by environmentally powered generators is lost or wasted. Inasmuch as the amount of electrical power supplied to the various power grids across the United States by environmentally powered generators is increasing, it can be seen that useful power is being wasted in connection with conversion to power grid frequencies.
Typical induction machines, like a motor or a generator, have a rotating element and a stationary element. These are sometimes called a rotor and a stator respectively. In a generator, mechanical power is supplied by a prime mover to rotate an input shaft to rotate the rotating element within the stationary element to obtain electrical power from the stationary element or stator. In a typical induction motor, the power is supplied to the stator to induce the rotor to rotate. In both, well-known principles of electromagnetism are involved with interacting magnet fields producing a torque between the two elements of such machines. Typical induction generators available today are configured to generate 60 Hz power. The prime mover is typically arranged or selected to provide a variable torque or power but at substantially fixed rotation rate.
Systems receiving variable speed input that produce constant frequency electrical output are not known. Indeed, systems for efficiently supplying electrical energy at a constant frequency using energy or torque delivered by a shaft powered by any prime mover that supplies power at a rotation rate that varies are not known.